Orihara Kouhei

Kouhei is a young man in his second-year in high school and the story's main protagonist. He lost his parents when he was very young, and is living at his aunt's house. He is a member of the light music club, but does not participate in club activities. He is always teasing his childhood friend, Nagamori Mizuka, and the new transfer student, Nanase Rumi but deep down he is nice to girls.

Spoiler

After his younger sister dies, he starts visiting the Eternal World, a mystical world parallel to the real world which is a major focus in the story. As time progresses, the people around him begin to slowly forget that he exists, and he starts trying to find someone to save his existence. He begins to confuse his childhood memories of his sister and Mizuka.